After decades of reminding people about the dangers of cigarettes, offering nicotine gum or patches and making smokers huddle outside, the government is turning to gruesome pictures.

Federal health officials Wednesday unveiled plans to replace the warnings cigarette packs began carrying 25 years ago with new versions using images that could include emaciated cancer patients, diseased organs and corpses.

Public health authorities and anti-smoking activists hailed the move as a milestone in the battle against tobacco in the United States that began in 1964 when the surgeon general first declared cigarettes a public health threat. That battle made steady progress for decades, but has been stymied in recent years, with a stubborn one in five adults and teens still smoking.

Tobacco remains the leading cause of premature and preventable death in the country, causing 443,000 deaths each year and about one-third of all cancer deaths.

Armed with new powers approved by Congress last year, the Food and Drug Administration is proposing warnings that include one containing an image of a man smoking through a tracheotomy hole in his throat; another depicting a body with a large scar running down the chest; and another showing a man who appears to be suffering a heart attack. Others have images of a corpse in a coffin and one with a toe tag in a morgue, diseased lungs and mouths, and a mother blowing smoke into a baby's face.

The new warnings will cover half the front and back of each pack and 20 percent of each large ad.

The FDA will gather public comment on 36 proposed images until Jan. 9 and select nine by June 22 after reviewing the scientific literature, the public comments and a study involving 18,000 people. Beginning Oct. 22, 2012, cigarette makers that do not put the new warnings on their packaging will not be allowed to sell their brands in the United States.

"When the rule takes effect, the health consequences of smoking will be obvious every time someone picks up a pack of cigarettes," FDA Commissioner Margaret A. Hamburg said.

The move was praised by public health and anti-tobacco activists, although some said they wished the warnings included other elements, such as a toll-free number to call for help quitting and messages about the benefits of quitting.

"In implementing the new warnings, the United States is catching up to scientific best practices," said Matthew Myers of the Campaign for Tobacco-Free Kids.

Others, however, criticized federal officials for not going further, such as by banning smoking in more places.

"Pictures on cigarette packs is a totally inadequate federal response," said John F. Banzhaf III, a professor of public health law at George Washington University who runs the activist group Action on Smoking and Health.